The present invention relates to a projection-type display apparatus that is preferably applied to a triple-plate type color projector using reflection-type spatial light modulating sections, and more particularly to an improvement for preventing deterioration of a projected picture or image and eliminating adverse influence of unnecessary polarized component as well as providing an arrangement of optical elements for downsizing the apparatus.
The triple-plate type color projector has a light source, such as a xenon lamp or a metal halide lamp, to generate white light. The white light is separated into three primary color beams. Each separated color beam is guided to a corresponding spatial light modulating section, such as a liquid crystal panel, to modulate each color beam in accordance with an image signal relating to a corresponding color. Thereafter, three modulated beams are combined to project the resultant composite light on a screen.
The color separating and light guiding system of this display apparatus is generally arranged in such a manner that the optical path of each separated color beam extending from the light source to a corresponding spatial light modulating section is identical in length with those of two other separated color beams. This arrangement is essentially important for obtaining a highly bright projection image as well as eliminating undesirable color shading.